Cerium oxide containing ceramic components and coatings in semiconductor processing equipment and methods of manufacture thereof

ABSTRACT

A corrosion resistant component of semiconductor processing equipment such as a plasma chamber comprises a cerium oxide containing ceramic material as an outermost surface of the component. The cerium oxide containing ceramic material comprises one or more cerium oxides as the single largest constituent thereof. The component can be made entirely of the cerium oxide containing ceramic material or, alternatively, the cerium oxide containing ceramic can be provided as a layer on a substrate such as aluminum or an aluminum alloy, a ceramic material, stainless steel, or a refractory metal. The cerium oxide containing ceramic layer can be provided as a coating by a technique such as plasma spraying. One or more intermediate layers may be provided between the component and the cerium oxide containing ceramic coating. To promote adhesion of the cerium oxide containing ceramic coating, the component surface or the intermediate layer surface may be subjected to a surface roughening treatment prior to depositing the cerium oxide containing ceramic coating.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the fabrication ofsemiconductor wafers, and, more particularly, to high density plasmaetching chambers having internal surfaces that reduce particle andmetallic contamination during processing.

2. Description of the Related Art

In the field of semiconductor processing, vacuum processing chambers aregenerally used for etching and chemical vapor depositing (CVD) ofmaterials on substrates by supplying an etching or deposition gas to thevacuum chamber and application of an RF field to the gas to energize thegas into a plasma state. Examples of parallel plate, transformer coupledplasma (TCP™) which is also called inductively coupled plasma (ICP), andelectron-cyclotron resonance (ECR) reactors and components thereof aredisclosed in commonly owned U.S. Pat. Nos. 4,340,462; 4,948,458;5,200,232 and 5,820,723. Because of the corrosive nature of the plasmaenvironment in such reactors and the requirement for minimizing particleand/or heavy metal contamination, it is highly desirable for thecomponents of such equipment to exhibit high corrosion resistance.

During processing of semiconductor substrates, the substrates aretypically held in place within the vacuum chamber by substrate holderssuch as mechanical clamps and electrostatic clamps (ESC). Examples ofsuch clamping systems and components thereof can be found in commonlyowned U.S. Pat. Nos. 5,262,029 and 5,838,529. Process gas can besupplied to the chamber in various ways such as by a gas distributionplate. An example of a temperature controlled gas distribution plate foran inductively coupled plasma reactor and components thereof can befound in commonly owned U.S. Pat. No. 5,863,376. In addition to theplasma chamber equipment, other equipment used in processingsemiconductor substrates include transport mechanisms, gas supplysystems, liners, lift mechanisms, load locks, door mechanisms, roboticarms, fasteners, and the like. Various components of such equipment aresubject to corrosive conditions associated with semiconductorprocessing. Further, in view of the high purity requirements forprocessing semiconductor substrates such as silicon wafers anddielectric materials such as the glass substrates used for flat paneldisplays, components having improved corrosion resistance are highlydesirable in such environments.

Aluminum and aluminum alloys are typically used for walls, electrodes,substrate supports, fasteners and other components of plasma reactors.In order to prevent corrosion of the such metal components, varioustechniques have been proposed for coating the aluminum surface withvarious coatings. For instance, U.S. Pat. No. 5,641,375 discloses thataluminum chamber walls have been anodized to reduce plasma erosion andwear of the walls. The '375 patent states that eventually the anodizedlayer is sputtered or etched off and the chamber must be replaced. U.S.Pat. No. 5,895,586 discloses that a technique for forming a corrosionresistant film of Al₂O₃, AIC, TiN, TiC, AlN or the like on aluminummaterial can be found in Japanese Application Laid-Open No. 62-103379.U.S. Pat. No. 5,680,013 states that a technique for flame spraying Al₂O₃on metal surfaces of an etching chamber is disclosed in U.S. Pat. No.4,491,496. The '013 patent states that the differences in thermalexpansion coefficients between aluminum and ceramic coatings such asaluminum oxide leads to cracking of the coatings due to thermal cyclingand eventual failure of the coatings in corrosive environments. U.S.Pat. No. 5,879,523 discloses a sputtering chamber wherein a thermallysprayed coating of Al₂O₃ is applied to a metal such as stainless steelor aluminum with an optional NiAl_(x) bond coating therebetween. U.S.Pat. No. 5,522,932 discloses a rhodium coating for metal components ofan apparatus used for plasma processing of substrates with an optionalnickel coating therebetween.

Materials for chamber walls, liners, rings and other parts of plasmachambers have also been proposed. See, for example, U.S. Pat. Nos.5,366,585; 5,788,799; 5,798,016; 5,851,299 and 5,885,356.

As integrated circuit devices continue to shrink in both their physicalsize and their operating voltages, their associated manufacturing yieldsbecome more susceptible to particle and metallic impurity contamination.Consequently, fabricating integrated circuit devices having smallerphysical sizes requires that the level of particulate and metalcontamination be less than previously considered to be acceptable.

In view of the foregoing, there is a need for high density plasmaprocessing chambers having internal, plasma exposed surfaces that aremore resistant to erosion and assist in minimizing contamination (e.g.,particles and metallic impurities) of the wafer surfaces beingprocessed.

SUMMARY OF THE INVENTION

In a first embodiment of the present invention, a process of making acomponent of semiconductor processing equipment is provided. The processincludes providing a cerium oxide containing ceramic layer on a surfaceof the component such that the cerium oxide containing ceramic layerforms an outermost surface of the component. The cerium oxide containingceramic layer comprises one or more cerium oxides as the single largestconstituent thereof.

In a second embodiment of the invention, a process of making a componentof semiconductor processing equipment from a cerium oxide containingceramic material is provided. The process includes steps of: preparing aslurry comprising cerium oxide; forming a green compact from the slurryin the desired shape; and sintering the green compact to form a ceriumoxide containing ceramic component. The cerium oxide containing ceramiccomponent comprises one or more cerium oxides as the single largestconstituent thereof.

In a third embodiment of the present invention, a component ofsemiconductor processing equipment is provided wherein the componentincludes a cerium oxide containing ceramic material forming an outermostsurface of the component. A plasma chamber including at least onecomponent as set forth above is also provided.

In a fourth embodiment of the present invention, a method of processinga semiconductor substrate in a plasma chamber as set forth above isprovided. In the method according to the present invention, a substrateis transferred into the plasma chamber and an exposed surface of thesubstrate is processed with a plasma. In a further preferred embodimentof the present invention, the method includes steps of: positioning thesubstrate on a substrate support in the reactor; introducing a processgas into the reactor; applying RF energy to the process gas to generatea plasma adjacent an exposed surface of the substrate; and etching orotherwise processing the exposed substrate surface with a plasma.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail with reference toaccompanying drawings in which like elements bear like referencenumerals, and wherein:

FIG. 1 illustrates a conventional plasma spray process;

FIG. 2 shows a cross-sectional view of a gas ring apparatus for apolysilicon etching apparatus according to one embodiment of the presentinvention;

FIG. 3 shows a polysilicon etch chamber containing components accordingto the present invention;

FIG. 4 shows a high density oxide etch chamber containing componentsaccording to the present invention;

FIG. 5 shows details of an embodiment of the corrosion resistant coatingaccording to the present invention;

FIG. 6 shows details of another embodiment of the corrosion resistantaccording to the present invention; and

FIG. 7 shows details of a further embodiment of the corrosion resistantaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The present invention provides an effective way to provide corrosionresistance to the surfaces of components of semiconductor processingapparatus such as parts of a plasma processing reactor chamber. Suchcomponents include chamber walls, substrate supports, gas distributionsystems (including showerheads, baffles, rings, nozzles, etc.),fasteners, heating elements, plasma screens, liners, transport modulecomponents, such as robotic arms, fasteners, inner and outer chamberwalls, etc., and the like. In the present invention, the componentsthemselves can be made from a cerium oxide containing ceramic materialor the plasma exposed surfaces of the components can be coated orotherwise covered with a cerium oxide containing ceramic material.

In the present invention, the cerium oxide containing ceramic materialcomprises one or more cerium oxides. According to the invention, thecerium oxide or oxides comprise the single largest constituent of theceramic material. The cerium oxide may be Ce(III) oxide or a Ce(IV)oxide. The cerium oxide containing ceramic material according to theinvention may also contain alumina, zirconia, yttria, and other oxides,nitrides, borides, fluorides and carbides of elements of Groups IIA,IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, and VB. The ceramicmaterial according to the invention may also comprise any oxide,nitride, boride, fluoride or carbide of any of the elements of theactinide series (e.g., those elements having an atomic number of 58-71).Particularly preferred materials in this group are cerium boride andcerium nitride.

In order to minimize contamination of substrates processed in equipmentincorporating one or more components according to the invention, it isdesirable for the cerium oxide containing ceramic material to be as pureas possible, e.g., include minimal amounts of contaminating elementssuch as transition metals, alkali metals or the like. For example, thecerium oxide containing material can be made pure enough to avoidon-wafer contamination of 10¹⁰ atoms/cm² or higher, preferably 10⁵atoms/cm² or higher.

The present inventors have discovered that cerium oxide based ceramicmaterials have desirable properties for use in semiconductor processingequipment such as plasma etch chambers. In particular, cerium oxidecontaining ceramics provide erosion resistant surfaces that can reducethe levels of particulate contamination in plasma reactor chambers.Cerium oxide containing ceramics can also provide plasma exposedsurfaces that are resistant to both physical attack (e.g., ion sputterinduced erosion) and chemical attack by the plasma.

In a preferred embodiment of the invention, the cerium oxide ceramicmaterial is provided as a coating. Cerium oxide coatings can be appliedby methods known in the art. Methods of applying cerium oxide coatingsare, for example, disclosed in U.S. Pat. Nos. 4,421,799; 4,593,007;5,334,462; 5,362,335; 5,627,124; 5,668,072; 5,721,057; 5,834,070; and6,007,880; and in patent publications GB 2236750A; and WO 94/29237.

A preferred coating method is thermal spraying (e.g., plasma spraying)in which ceramic powder is melted and incorporated in a gas streamdirected at the component being spray coated. An advantage of thermalspraying techniques is that the component is coated only on the sidesfacing the thermal spray gun, and masking can be used to protect otherareas. Conventional thermal spraying techniques, including plasmaspraying, are addressed in The Science and Engineering of Thermal SprayCoating by Pawlowski (John Wiley, 1995), the contents of which arehereby incorporated by reference.

A particularly preferred thermal spraying method is plasma sprayingwhich allows intricate interior surfaces of the chamber or other chambercomponents to be coated. FIG. 1 illustrates a typical plasma sprayingprocess. The coating material, usually in the form of a powder 112, isinjected into a high temperature plasma flame 114 where it is rapidlyheated and accelerated to a high velocity. The hot material impacts onthe substrate surface 116 and rapidly cools to form a coating 118.

The plasma spray gun 120 typically comprises a copper anode 122 andtungsten cathode 124, both of which are water cooled. Plasma gas 126(e.g., argon, nitrogen, hydrogen, helium) flows around the cathode inthe direction generally indicated by arrow 128 and through an anode 130which is shaped as a constricting nozzle. The plasma is initiated by ahigh voltage discharge which causes localized ionization and aconductive path for a DC arc to form between the cathode 124 and theanode 130. Resistance heating from the arc causes the gas to reachextreme temperatures, dissociate and ionize to form a plasma. The plasmaexits the anode nozzle 130 as a free or neutral plasma flame (plasmawhich does not carry electric current). When the plasma is stabilizedready for spraying, the electric arc extends down the nozzle. Powder 112is fed into the plasma flame usually via an external powder port 132mounted near the anode nozzle exit 134. The powder 112 is so rapidlyheated and accelerated that the spray distance 136 (the distance betweenthe nozzle tip and the substrate surface) can be on the order of 125 to150 mm. Plasma sprayed coatings are thus produced by a process in whichmolten or heat-softened particles are caused to impact on a substrate.

In the present invention, surface preparation techniques such ascleaning and grit or bead blasting can be used to provide a morechemically and physically active surface for bonding. Prior to coating,the surface of the substrate is preferably thoroughly cleaned to removesurface material such as oxides or grease. Further, the surface can beroughened by known methods such as grit blasting prior to coating. Bygrit blasting, the surface area available for bonding can be increasedwhich can increase the coating bond strength. The rough surface profilecan also promote mechanical keying or interlocking of the coating withthe substrate. For aluminum reactor components, it is particularlydesirable to roughen the component surface, anodize the roughenedcomponent surface and again roughen the anodized surface prior toapplication of the cerium oxide coating.

The cerium oxide containing ceramic coating according to the inventionis preferably applied using a plasma spray process but other coatingmethods suitable for use with ceramic materials may also be employed.For example, the cerium oxide containing ceramic coating according tothe invention can be applied by sputtering, sputter deposition,immersion coating, chemical vapor deposition, evaporation andcondensation (including electron beam evaporation and condensation),physical vapor deposition, hot isostatic pressing, cold isostaticpressing, compression molding, casting, compacting and sintering, plasmaspraying, and thermal spraying.

In a preferred embodiment of the invention, the cerium oxide containingceramic components are used as reactor components in a polysiliconhigh-density plasma reactor. An exemplary reactor of this type is theTCP 9400™ plasma etch reactor available from Lam Research Corporation ofFremont, Calif. In the TCP 9400™ reactor, processing gases (such as Cl₂,HBr, CF₄, CH₂F₂, O₂, N₂, Ar, SF₆ and NF₃) are conducted into a gas ringlocated on the bottom of the etch chamber and are then guided throughgas holes into the reactor chamber. FIG. 2 shows a cross-sectional viewof a gas ring for a TCP 9400™ polysilicon etch reactor according to thepresent invention. As shown in FIG. 2, the main body of the gas ring 40surrounds a substrate support 44. The bottom surface of the gas ring 40contains a ring-shaped gas-guiding trench 60. The aforementioned gasholes 50 extend into the gas-guiding trench 60.

The gas ring is typically composed of aluminum. The upper surfaces ofthe gas ring are directly exposed to the plasma and are thus subject toerosion. To protect these surfaces, the gas ring is typically coveredwith an aluminum oxide layer which is typically formed by anodizing thesurface of the gas ring. The anodized coating, however, is relativelybrittle and has a tendency to crack during repeated thermal cycling ofthe reactor during use. The cracks which form in the anodized layer canallow the corrosive process gases to attack the underlying aluminumlayer reducing part life and contributing to metallic and particlecontamination of processed substrates such as wafers, flat panel displaysubstrates, etc.

According to the present invention, the exposed surfaces of the gas ringcan be covered with a coating 42 of a cerium oxide containing ceramicmaterial. The cerium oxide ceramic can be coated on a bare (with orwithout a native oxide surface film) aluminum layer or on an aluminumoxide layer (e.g., aluminum having an anodized surface). When coatingthe gas ring, the coating can be allowed to partially penetrate into thegas holes to coat and protect the inside walls thereof. However, thecoating material should not be applied in such a manner as to obstructthe openings. Therefore, the gas holes can be plugged or masked duringthe coating process.

Other components of the TCP 9400™ polysilicon etch reactor which can beexposed to the plasma during processing can also be coated with a ceriumoxide containing ceramic material according to the present invention.These components include chamber walls, chamber liners, chucking devicesand the dielectric window opposite the substrate. Providing a coating ofcerium oxide containing ceramic material on the upper surface of achucking device such as an electrostatic chuck provides additionalprotection to the chuck during cleaning cycles in which a wafer is notpresent and the upper surface of the chuck is thus directly exposed tothe plasma.

Another exemplary polysilicon etch reactor is the Versys™ PolysiliconEtcher or 2300™ etcher also available from Lam Research Corporation ofFremont, Calif. FIG. 3 shows a cross-sectional view of a 2300™polysilicon etch reactor according to the present invention. The reactorcomprises a reactor chamber 150 that includes a substrate support 152including an electrostatic chuck 154 which provides a clamping force toa substrate (not shown) mounted thereon. A focus ring 170 is shownmounted on substrate support 152 around electrostatic chuck 154.Substrate support 152 can also be used to apply an RF bias to thesubstrate. The substrate can also be back-cooled using a heat transfergas such as helium. In the 2300™ etcher, processing gases (e.g., Cl₂,HBr, CF₄, CH₂F₂, O₂, N₂, Ar, SF₆ and NF₃) are introduced into chamber150 via a gas injector 168 located on the top of chamber 150. Gasinjector 168 is connected to a gas feed 156. Gas injector 168 istypically made of quartz or a ceramic material such as alumina. Asshown, an inductive coil 158 can be powered by a suitable RF source (notshown) to provide a high density (e.g., 10¹¹-10¹² ions/cm³) plasma.Inductive coil 158 couples RF energy through dielectric window 160 intothe interior of chamber 150. Dielectric window 160 is typically made ofquartz or alumina. Dielectric window 160 is shown mounted on an annularmember 162. Annular member 162 spaces dielectric window 160 from the topof chamber 150 and is referred to as a “gas distribution plate”. Chamberliner 164 surrounds substrate support 152. Chamber 150 can also includesuitable vacuum pumping apparatus (not shown) for maintaining theinterior of the chamber at a desired pressure.

In FIG. 3, the internal surfaces of reactor components such as theannular member 162, the dielectric window 160, the substrate support152, the chamber liner 164, the gas injector 168, the focus ring 170 andthe electrostatic chuck 154, are shown coated with a coating 166 of acerium oxide containing ceramic material. The interior surfaces ofchamber 150 and substrate support 152 below chamber liner 164 can alsobe provided with a coating 166 of a cerium oxide containing ceramicmaterial as shown in FIG. 3. Any or all of these surfaces as well as anyother internal reactor surface can be provided with a cerium oxidecontaining ceramic coating according to the present invention. Further,any or all of these components can be manufactured from monolithicbodies of a cerium oxide containing ceramic material according to theinvention.

The reactor components of the present invention can also be used in ahigh-density oxide etch process. An exemplary oxide etch reactor is theTCP 9100™ plasma etch reactor available from Lam Research Corporation ofFremont, Calif. In the TCP 9100™ reactor, the gas distribution plate isa circular plate situated directly below the TCP™ window which is alsothe vacuum sealing surface at the top of the reactor in a plane aboveand parallel to a semiconductor wafer. The gas distribution plate issealed using an O-ring to a gas distribution ring located at theperiphery of the gas distribution plate. The gas distribution ring feedsgas from a source into the volume defined by the gas distribution plate,an inside surface of a window underlying an antenna in the form of aflat spiral coil supplying RF energy into the reactor, and the gasdistribution ring. The gas distribution plate contains an array of holesof a specified diameter which extend through the plate. The spatialdistribution of the holes through the gas distribution plate can bevaried to optimize etch uniformity of the layers to be etched, e.g., aphotoresist layer, a silicon dioxide layer and an underlayer material onthe wafer. The cross-sectional shape of the gas distribution plate canbe varied to manipulate the distribution of RF power into the plasma inthe reactor. The gas distribution plate material is dielectric to enablecoupling of this RF power through the gas distribution plate into thereactor. Further, it is desirable for the material of the gasdistribution plate to be highly resistant to chemical sputter-etching inenvironments such as oxygen or a hydro-fluorocarbon gas plasma in orderto avoid breakdown and the resultant particle generation associatedtherewith.

FIG. 4 illustrates a plasma reactor of the aforementioned type. Thereactor comprises a reactor chamber 10 that includes a substrate holder12 including an electrostatic chuck 34 which provides a clamping forceto a substrate 13 as well as an RF bias to a substrate. The substratecan be back-cooled using a heat transfer gas such as helium. A focusring 14 comprises a dielectric outer ring 14 a and an inner ring 14 bwhich confines plasma in an area above the substrate. A source of energyfor maintaining a high density (e.g., 10¹¹-10¹² ions/cm³) plasma in thechamber such as an antenna 18 powered by a suitable RF source to providea high density plasma is disposed at the top of reactor chamber 10. Thechamber includes suitable vacuum pumping apparatus for maintaining theinterior of the chamber at a desired pressure (e.g., below 50 mTorr,typically 1-20 mTorr).

A substantially planar dielectric window 20 of uniform thicknessprovided between the antenna 18 and the interior of the processingchamber 10 forms the vacuum wall at the top of the processing chamber10. A gas distribution plate 22 is provided beneath window 20 andincludes openings such as circular holes for delivering process gas fromthe gas supply 23 to the chamber 10. A conical liner 30 extends from thegas distribution plate and surrounds the substrate holder 12. Theantenna 18 can be provided with a channel 24 through which a temperaturecontrol fluid is passed via inlet and outlet conduit 25, 26. However,the antenna 18 and/or window 20 need not be cooled or could be cooled byother techniques such as by blowing air over the antenna and window,passing a cooling medium through or in heat transfer contact with thewindow and/or gas distribution plate, etc.

In operation, a semiconductor substrate such as a silicon wafer ispositioned on the substrate holder 12 and held in place by anelectrostatic chuck 34. Other clamping means, however, such as amechanical clamping mechanism can also be used. Additionally, heliumback-cooling can be employed to improve heat transfer between thesubstrate and chuck. Process gas is then supplied to the vacuumprocessing chamber 10 by passing the process gas through a gap betweenthe window 20 and the gas distribution plate 22. Suitable gasdistribution plate arrangements (i.e., showerhead) arrangements aredisclosed in commonly owned U.S. Pat. Nos. 5,824,605; 6,048,798; and5,863,376. A high density plasma is ignited in the space between thesubstrate and the window by supplying suitable RF power to the antenna18.

In FIG. 4, the internal surfaces of reactor components such as the gasdistribution plate 22, the chamber liner 30, the electrostatic chuck 34,and the focus ring 14 are shown coated with a coating 32 of a ceriumoxide material. However, any or all of these surfaces can be providedwith a cerium oxide coating according to the present invention.

The high density polysilicon and dielectric etch chambers describedabove are only exemplary of plasma etch reactors which can incorporatecomponents according to the present invention. The cerium oxidecontaining ceramic components of the present invention can be used inany etch reactor (e.g., a metal etch reactor) or other type ofsemi-conductor processing equipment where plasma erosion is a problem.

Other components which may be provided with cerium oxide coatingsinclude chamber walls (typically made from aluminum having an anodizedor non-anodized surface), substrate holders, fasteners, etc. These partsare typically made from metal (e.g., aluminum) or ceramic (e.g.,alumina). These plasma reactor components are typically exposed toplasma and often show signs of corrosion. Other parts which can becoated in accordance with the present invention may not be directlyexposed to plasma but instead are exposed to corrosive gases such asgases emitted from processed wafers or the like. Therefore, otherequipment used in processing semiconductor substrates can also beprovided with cerium oxide containing ceramic surfaces according to thepresent invention. Such equipment can include transport mechanisms, gassupply systems, liners, lift mechanisms, load locks, door mechanisms,robotic arms, fasteners, and the like.

Examples of metals and/or alloys that can be coated with a cerium oxidecontaining ceramic material according to the present invention includealuminum, stainless steel, refractory metals, e.g., “HAYNES 242”“Al-6061”, “SS 304”, “SS 316”. Since the cerium oxide containing ceramicmaterial forms a corrosion resistant coating over the component, theunderlying component is no longer directly exposed to the plasma andaluminum alloys can be used without regard to alloying additions, grainstructure or surface conditions. Additionally, various ceramic orpolymeric materials may also be coated with a cerium oxide containingceramic material according to the present invention. In particular, thereactor components can be made from ceramic materials such as alumina(Al₂O₃), silicon carbide (SiC), silicon nitride (Si₃N₄), boron carbide(B₄C) and/or boron nitride (BN).

If desired, one or more intermediate layers of material can be providedbetween the cerium oxide containing ceramic coating and the surface ofthe component. FIG. 5 shows a coated component according to a preferredembodiment of the present invention. As shown in FIG. 5, a firstintermediate coating 80 is optionally coated on a reactor component 70by a conventional technique. The optional first intermediate coating 80is sufficiently thick to adhere to the substrate and to further allow itto be processed prior to forming the optional second intermediatecoating 90 or the cerium oxide coating described below. The firstintermediate coating 80 can have any suitable thickness such as athickness of at least about 0.001 inches, preferably from about 0.001 toabout 0.25 inches, more preferably between 0.001 and 0.15 inches andmost preferably from 0.001 inches to 0.05 inches.

After depositing the optional first intermediate coating 80 onto thereactor component 70, the plating can be blasted or roughened by anysuitable technique, and then overcoated with the second optional coating90 or the cerium oxide containing ceramic coating 100. A roughened layer80 provides a particularly good bond. Desirably, the second intermediatecoating 90 imparts a high mechanical compression strength to the coating80 and minimizes formation of fissures in the coating 90.

The optional second intermediate coating 90 is sufficiently thick toadhere to the first intermediate coating 80 and to further allow it tobe processed prior to forming any additional intermediate coatings orthe outer cerium oxide containing ceramic coating 100 described below.The second intermediate coating 90 can have any suitable thickness suchas a thickness of at least about 0.001 inches, preferably from about0.001 to about 0.25 inches, more preferably between 0.001 and 0.15inches and most preferably from 0.001 inches and 0.05 inches.

The first and second intermediate coating may be made of any one or morematerials employed in conventional plasma processing chambers. Examplesof such materials include metals, ceramics and polymers. Particularlydesirable metals include refractory metals. Particularly desirableceramics include Al₂O₃, SiC, Si₃N₄, BC, AIN, TiO₂, etc. Particularlydesirable polymers include fluoropolymers such aspolytetrafluoroethylene and polyimides. The intermediate coating orcoatings can be applied by any known deposition technique such asplating (e.g., electroless plating or electroplating), sputtering,immersion coating, chemical vapor deposition, physical vapor deposition,electrophoretic deposition, hot isostatic pressing, cold isostaticpressing, compression molding, casting, compacting and sintering, andthermal spraying (e.g., plasma spraying).

It is contemplated that the first and second intermediate layers 80 and90, which are optional may be any one of the above-mentioned materialssuch that the coatings are the same or different depending on thedesired properties. Additional intermediate coatings such as a third,fourth or fifth intermediate coating of the same or different materialsmay also be provided between the coating and the substrate.

FIG. 6 shows details of a second embodiment of the corrosion resistantcoating. The cerium oxide containing ceramic layer 100 can be depositedonto reactor component 70 to a suitable thickness such as a thickness inthe range of about 0.001 to about 1.0 inch, preferably 0.001 to 0.5 inchthick and most preferably 0.001 inches to 0.05 inches. The thickness ofthe ceramic layer can be selected to be compatible with the plasmaenvironment to be encountered in the reactor (e.g., etching, CVD, etc.).

Although thermal spraying is a preferred method of providing componentshaving cerium oxide containing ceramic surfaces, other coating methodsmay also be employed. The cerium oxide containing coating, for example,can also be applied by other deposition techniques such as sputtering,immersion coating, chemical vapor deposition, physical vapor deposition,hot isostatic pressing, cold isostatic pressing, compression molding,casting, and compacting and sintering.

The cerium oxide containing ceramic material can also be provided in theform of preformed liners adapted to cover the exposed surfaces ofreactor components. These liners can be attached by any known meansincluding adhesive bonding or by the use of mechanical fasteners. Whenfasteners are used, the fasteners themselves, if exposed to the plasma,should also be made from an erosion resistant material. Additionally,the cerium oxide containing ceramic liners may be designed to interlockwith the underlying reactor component.

In yet another embodiment, components of semiconductor processingequipment are manufactured as monolithic bodies from cerium oxidecontaining ceramic material. Sintered monolithic bodies of cerium oxideceramics are disclosed, for example, in U.S. Pat. Nos. 2,434,236 and4,465,778.

A method of manufacturing monolithic bodies from cerium oxide containingceramic materials may include preparing a cerium oxide containingslurry, forming a green compact in the desired shape, and sintering thecompact. The green compact can be formed in the shape of anyplasma-exposed reactor component. Such components can include chamberwalls, substrate supports, gas distribution systems includingshowerheads, baffles, rings, nozzles, etc., fasteners, heating elements,plasma screens, liners, transport module components, such as roboticarms, fasteners, inner and outer chamber walls, etc., and the like. Aspecific example of such a component is reactor component 110 shown inFIG. 7. FIG. 7 illustrates a detail of the cross-section of reactorcomponent 110 constructed as a monolithic body manufactured from acerium oxide containing ceramic material. Details of ceramic processingtechniques are given in Introduction to Ceramics, 2^(nd) Edition, by W.D. Kingery, H. K. Bowen, and D. R. Uhlmann (J. Wiley & Sons, 1976), thecontents of which are hereby incorporated by reference.

The cerium oxide containing ceramic material can be provided on all orpart of the reactor chamber and components. In a preferred embodiment,the coating or covering is provided on the regions that can be exposedto the plasma environment such as parts in direct contact with theplasma or parts behind chamber components (e.g., liners). Additionally,it is preferred that the cerium oxide layer be applied to regions thatmay be subjected to relatively high bias voltages (i.e. relatively highsputter ion energies).

By either applying a cerium oxide containing ceramic layer as a coatingor covering or constructing a monolithic cerium oxide containing ceramiccomponent in accordance with the invention, several advantages arerealized. Namely, by employing cerium oxide containing ceramicsaccording to the present invention, lower erosion rates can be realized.As a result, the cerium oxide containing ceramic components or coatingsaccording to the present invention can decrease levels of metal andparticulate contamination, lower costs by increasing the lifetime ofconsumables, decrease process drifts and reduce the levels of corrosionof chamber parts and substrates.

1. A process for coating a surface of a component of semiconductorprocessing equipment, the process comprising: depositing a cerium oxidecontaining ceramic layer on a surface of a component of semiconductorprocessing equipment, wherein the cerium oxide containing ceramic layercomprises one or more cerium oxides as the single largest constituentthereof and wherein the cerium oxide containing ceramic layer forms anoutermost surface of the component.
 2. The process according to claim 1,wherein the cerium oxide comprises Ce(III) oxide and/or Ce(IV) oxide. 3.The process according to claim 1, wherein the ceramic layer is appliedby a technique selected from the group consisting of sputtering, sputterdeposition, immersion coating, chemical vapor deposition, electron beamevaporation and condensation, physical vapor deposition, hot isostaticpressing, cold isostatic pressing, compression molding, casting,compacting and sintering, plasma spraying, and thermal spraying.
 4. Theprocess according to claim 1, wherein the component is selected from thegroup consisting of a plasma chamber wall, a chamber liner, a gasdistribution plate, a gas ring, a pedestal, a dielectric window, anelectrostatic chuck and a focus ring.
 5. The process according to claim1, wherein the ceramic layer is deposited to a thickness ranging fromabout 0.001 to about 0.050 inches.
 6. The process according to claim 1,further comprising depositing an intermediate layer on the surface ofthe component and depositing the ceramic layer on the intermediatelayer.
 7. The process according to claim 1, further comprisingsubjecting the surface to a surface roughening treatment prior todepositing the ceramic layer, the ceramic layer being deposited on theroughened surface.
 8. The process according to claim 7, wherein thesurface is aluminum, the process further comprising anodizing theroughened surface before depositing the ceramic layer.
 9. The processaccording to claim 8, further comprising subjecting the anodized surfaceto a surface roughening treatment prior to depositing the ceramic layer10. The process according to claim 1, wherein the surface is a metalsurface. 11-19. (Canceled).
 20. A method of processing a semiconductorsubstrate in a plasma chamber containing the component of claim 11, themethod comprising contacting an exposed surface of the semiconductorsubstrate with plasma.
 21. A method of manufacturing a component ofsemiconductor processing equipment constructed from a cerium oxidecontaining ceramic material comprising the steps of: preparing a slurrycomprising a cerium oxide containing ceramic material; forming a greencompact from the slurry in the desired shape; and sintering the greencompact to form a cerium oxide containing ceramic component; wherein thecerium oxide containing ceramic component comprises one or more ceriumoxides as the single largest constituent thereof.
 22. A component ofsemiconductor processing equipment manufactured by the method of claim21.
 23. The method according to claim 21, wherein the cerium oxidecomprises Ce(III) oxide and/or Ce(IV) oxide.